Sewing-machine



l. WHITELAW.

SEWING MACHINE.

APPLICATION FILED APR. II, 1911.k

1,365,427, Patented Jan. 11,1921. y

4 SHEETS-SHEET l.

J. WHITELAW.

SEWING MACHINE.

APPLICATION FILED APR. II, Isn.

1,365,427r Patentd Jan. 11, 1921.

4 SHEETS-SHEET 2` 1. wmTELAw.

SEWING MACHINE. APPLlcmon man APR. 11, 1911.

` 1,365,427.. Patented Jam 11,1921.

4 SHEETS-SHEET 3.

'1. WHIIELAW.

SEWING MACHINE.

APPLICATION FILED APR. II, 1911.

1365,42?. Patented Jan. 11, 1921.

4 SHEETS-SHEET 4.

to point PATENT oFFlcE.

JAMESWHITEIAW, OF ST. LOUIS, MISSOURI.

SEWING-MACHINE.

Specification of Letters Patent.

Patented Jan. 11, 1921.

Applicatin filed April 11, 1917. Serial No. 161,327.

To all whom t may concern:

Be it known that I, JAMES WHrrELAw, a citizen of the United States, residing at St. Louis, State of Missouri, have invented certain new and useful Improvements in Sewing-Niachines, of which the following is a specification.

My invention relates to improvements in sewing machines, and in some of its features particularly to a blind stitch machine for working on fur, as in attaching the fur to a fabric backing.

More particularly an object of my invention is to provide a Work handling and feeding mechanism for such a blind stitch machine whereby the work may be fed and presented to theI needlewith minimumlikelihood to injury and yet with facility for high speed progress and ease ofmanipulation by the operator.

In the drawings wherein I have illustrated an embodiment of my invention in a chain stitch type of machine,

Figure 1 isa side elevation of the complete `machine with parts broken away and with the front cover plate removed;

Fig." v2 lis `an end elevation;

Fig. 3 is a perspective view of fragments of the work handling mechanism; and

Figs. 4:, 5 and 6 are respectively sections on lines JL- 4, 5-5 and 6-6 of Fig. 2.

Fig. 7 is a detail section of the main feed cam. i

The blind stitch machine shown in the drawings has a frame 10 comprising the upper and lower arms 11 and 12 and the intervening post or standard 13. The upper arm carries a suitable stitch forming mechanism 14, herein shown as of the chain stitch type, comprising 'a curved reciprocating needle 15 and a complemental looperfmechanism 16, both arranged to work above a stationary presser foot 17 whichfprotrudes toward the operator from thelower ypart of the endof the yupper arm and `that has therein an aperture 18through which the goods may be presented to the needle. y j

With the specific devices of the stitch forming mechanism the present invention is not concerned, as various stitch-forming mechanisms may be employed, and it suliices out that in the construction shown the main shaft 20, which extends longitudinally through the upper arm 12, drives the needle in reciprocation transversely 'to the direction of feed, andactuates the -way,

double-point looper through mechanism substantial y as described in my Patent No. 1,190,833 dated July 11th, 1916.

The work handling mechanism includes a plunger vertically reciprocable from below the presser-foot to present bends of the work to the needle through the opening 18 in the presser foot, and while various constructions to this end may be employed, the particular structure herein shown for illustration comprises means of the character fully described in my prior Patent No. 1,198,800. It` sufficeshere to point out that such mechanism includes a link and lever system 22 operated by an eccentric 23 on the main shaft 20 and serving to rock, to an extent adjustably limited, the torsionally yieldable shaft 24 that extends through the lower arm, and that, by a suitable crank mechanism 25, operates the vertically reciprocable plunger 26 to bring it, oneachup-stroke to a position where it bends the work into the needle-path through the presser foot opening. This plunger, of course, is timed to rise just before the penetration stroke of the needle and not between feed-operations.

The feed mechanism comprises lower and upper feed dogs 30 and 31 arranged below the presser foot, respectively below and above the work, for cooperation to grasp the material between them and advance it .through the machine atthe proper time in the cycle of rotation of the main shaft.

yEach of these feed dogs is preferably positively driven in its fore-and-aft, or feeding, movements and each is provided with means for independently adjusting the length of its'feeding throw. With the main or lower feed dog, there is preferably associated a ,work-clamp that, when the dog is feeding,

disengages the work,-but, when the dog is idly returning, clamps against the workto `'pervent retrogression ork other unintended displacements thereof. The clamp mechanism may be disposed substantially `after the fashion described in my said prior Patent The feed dog plate also has link connection 36 extending to a mid-portion of lever 37 and this lever has one end tonnected to the crank 38 of rock shaft 39 which receives its motion from a cam 40 on the main shaft 20, through suitable linkage as described in my prior patent. Thus the crank 38 controls the up-and-down component of the fourway motion of the feed dog 30. The other end of lever 37 is pivoted to a link 41 that has pivotal connection with the clamp member 42, which is mounted for vertical reciprocation and is normally springpressed upwardly through the crank 43 of a shaft 44 that carries another crank 45 which is acted on by a spring 46. Raising lever 45 will depress the main feed dog and the clamp. By this mechanism, all substantially as described in my prior patent, the feed dog is caused to make its movement in coperative relation with the clamp, the dogs advancing movement being made while it is pressed against the presser foot or the work and while the clamp 42 is depressed, and the dogs retraction occurring while it is depressed and the clamp member 42 is raised to hold the work against the underside of the presser foot.

In specific construction I prefer that the clamp member 42 shall flank both sides of the plunger, and shall have a relatively eX- tensive top surface toothed, as at 46 in the direction of feed to guard against'lateral movement of the work under the transverse needle-thrusts or otherwise; and also I prefer that the feed dog 30 shall be suitably cut away so that portions thereof respectively flank the pressure member and lie in advance thereof. The dog 80 has a series of coarse teeth forming a feed surface7 47, paralleling one side of the clamp member and another feed surface or toothed portion 48 directly in advance of the plunger 26 and of the clamp. The outer portion 49 of the dog may be smooth and lower than the crests of the feed-surface teeth.

rIhe upper feed dog 3l, is arranged to slide fore-and-aft along the under-side of the presser foot, and specifically I prefer to construct this element in the form of a forked plate having, in parallelism, a long finger 31L and a short finger 31h, the former toothed to a'ord a feed point 47 to overlie and aline with the feed surface 47, and the short arm correspondingly provided with a serrated portion or feed point 48 for similar relation to the feed surface 48. These fingers ofthe fork are arranged to slide in grooves, as that shown at 50, in the underside of the presser foot, so that they are nearly flush with, or a trifle short of, the surface of the latter, the teeth of the feed surface being ne and rather shallow. The strip of metal forming this upper feed member is given a quarter twist, beyond the presser foot and its extremity is pivoted, as at 51, to the end of a lever 52, fulcrumed near its center on a bearing 53 and having its upper end provided with an arcuate slot 54 engaged by a bolt 55 pivoted in an eccentric link 56, the strap portion of which surrounds the eccentric 57 secured on the drive shaft 20. By adjustment of the bolt 55 in the slot 54 the throw of the upper feed dog may be varied. A spring 57, between the upper feed dog and frame, maintains the feed dog always in close sliding contact with the under-side of the presser foot, so that the upper feed dog has effectively only a 2-way movement.

It will be apparent that the independent adjustability and positive actuation of the upper and lower feed dogs through positive connections with the main shaft enables them to be brought into perfect unison in feeding throw, so that the work may be carried forward in a clamped condition that prevents any slippage as between different plies of the work, butthat, as is sometimes desirable, for the purpose of creating a fullness between plies or to accommodate other special conditions, either feed element may be adjusted so that its positive feeding action is greater or less than the action of the other dog.

It will be noted that the upper feed dog, housed within the grooves of the presser foot, has no material tendency to retract the work as the dog slides toward the oper ator on its idle stroke.

It will be understood by those skilled in the art that while I have described my invention particularly with reference to its embodiment in a machine of general construction identiiied in certain of my prior patents, the features of my present invention are susceptible of embodiments in connection with other general structures of chines and are susceptible of variation in details of construction and arrangement without departure from the spirit of my invention and within the scope of the appended claims.

Having described my invention, what I claim is 1. In a sewing machine, the combination of a stationary presser foot having an aperture, stitch-forming mechanism thereabove, means to present the work through the presser foot opening, a feed dog below said presser foot, means for imparting four-way movement to said feed dog, adjustable to vary its feeding throw, an upper feed dog below thek presser foot registering with the lower dog, and means for imparting twoway movement to said upper dog adjustable to vary its feeding throw.

2. In a sewing machine of the character described the combination with a stationary presser foot having a work receiving opening, stitch forming means operating above said presser foot, plunger means for presenting the worlr through the presser foot opening to the needle, and clamp means to clamp the work against the under side of the presser foot, of work-feeding means alternating i-n operation with the clamp means and comprising a lower feed dog below the work and an upper feed dog registering therewith and sliding along the under side of the presser foot, and two means for imparting fore-and-aft motion to said respective feed dogs, said two means independently adjustable to determine the respective lengths of throw of said feed dogs.

3. In a machine of the character described the combination of a stationary presser foot, stitch forming mechanism above said presser foot, work handling mechanism below said presser foot, including a clamp member, a four-way feed member, partially embracing said clamp member, and means for operating said feed and clamp member for alternative cooperation with the work, and an auxiliary feed member, sliding againstthe under side of the presser foot, means for imparting two way motion to said upper feed member, and means for adjusting the throw of said upper feed member.

4L. In a sewing machine, the combination of a stationary presserfoot having an aperture and having grooves in its under side, stitch-forming mechanism above said presserfoot, means to present the work through the presserfoot opening, an upper feed dog slidable in said presserfoot grooves, means for reciprocating said feed member, adjustable to vary its throw, a lower feed member alining with the upper feed member, means for imparting four-way movement to the lower feed member, means for adjusting its feeding throw, and means for bodily lower'- ing said lower feed member.

5. In a machine of the character described having an apertured presser foot grooved on its under-side, stitch-forming means above said presser foot, and means below the presser-foot to present the work to the needle through the aperture; of an upper feed dog slidable in the presser-foot grooves, a lever for reciprocating the same, adjustable means for vibrating the lever to different extents; a lower feed dog, means for imparting fourway motion to the lower feed dog, and means for adjusting the throw of the last said means.

6. In a sewing machine, the combination of a stationary presserfoot having a workopening, Stich-forming mechanism above said work-opening, means below the presserfoot to present the work through said opening to the stitch-forming means, a pair of feed dogs in superimposed relation below the presserfoot, one of said dogs slidable along the underside of the presserfoot, means for reciprocating said slidable dog, means for imparting four-way motion to the opposing dog, and means for lowering the last named dog bodily.

7. In a sewing machine, the combination of a stationary presserfoot having a workopening, stitch-forming mechanism above said work-opening, means below the presserfoot to present the work through said opening to the stitch-forming means, a pair of feed dogs in superimposed relation below the presserfoot, one of said dogs slidable along he underside of the presserfoot, means for reciprocating said slidable dog, means for imparting four-way motion to the opposing dog, means for lowering the lastnamed dog bodily, and means for adjusting the feeding throw of each of said dogs independently of the other.

In testimony whereof I hereunto set my hand in the presence of two subscribing witnesses.

JAMES WHITELAW.

In the presence of- N. G. BUTLER, CHARLES A. BECKER. 

